Automatic blow-off device.



rn sra'rns Parana ernten.

FRANK ROBERSON DEXTER, 0F DAYTON,

OHIO.

Specification of Letters Patent.

Patented Feb. 11, 1919.

Application led January 30, 1918. Serial No. 214,470.

To all whom t may concern:

Be it known that I, FRANK RoBERsoN DEXTER, a citizen of the United States, and a resident of Dayton, in the county of Montgomery and State of Ohio, have invented a new and Improved Automatic Blow-Off Device, of which the following is a full, clear, and'exact description.'

his invention relates to steam boilers or other analogous appliances and has particular reference to attachments for such appliances whereby predetermined or regulated quantities of the contents thereof are adapted to be delivered therefrom.

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More denitely stated among the objects of this invention' is to provide an attachment` for a steam boiler whereby any deposits of sediment, scale, sand, grit, or other solid particles may be discharged om within the boiler by means operated automatically at any desired rate of speed by reason of the internal pressure.

A further object of the invention is to provide an attachment of the general character above indicated for connection to or use in conjunction with the blow-oil pipe of a steam boiler whereby, as a result of certain adjustments to be described fully below, either the whole of the contents of the boiler may be discharged directly into the sewer or other place of delivery, or else regulatable quantities less than all of the contents may be discharged. By the use of the term steam boiler herein I desire it to be distinctly understood that I mean to cover not only steam boilers proper but feed water heaters or other containers having relatively high internal pressure. v

With .the foregoing and other objects in view the invention consists in the arrangement and combination of parts hereinafter described and claimed, and .while the invention is not restricted to the exact details of construction disclosed or suggested herein still for the purpose of illustrating a practical embodiment thereof reference is had to the accompanying drawings, in

which like reference characters designate the same parts in the several views, and in whichv.

Figure 1 is a vertical longitudinal-section of my improvement.

Fig. 2 is a similar view, butwith the reciprocating piston in the p'os1t1on in which it is presumed to be moving toward the right; and

.Fig 3 is an enlarged detail view of the pilot valve in open position.4

Referring now more particularly to the drawlngs I show al device comprising a mam easing or body 10 comprising two main chambers 11 and 12 in the nature of coaxial cylinders, the former being smaller in cross section than the latter.

13 indicates a blow-oli pipe leading from the boiler or a yconnection with the blowoif pipe. This member which will be referred to herein as the blow-ottl pipe is tapped into or otherwise secured to the nipple portion 14 of the body from which a passageway 15 leads into the smaller cylinder or chamber l1. In line, however, with the blow-ofi'l pipe I provide a by-pass i 16 leading directly to the delivery pipe 17 connected with the discharge nipple 18 at the lower portion of the body, this nipple being in communication with the larger cylinlcller 12 beyond the end of the cylin- At one side of the cylinder 11, preferably the upper side, is connected through a neck 19 a closed chamber 20 or dome of any?r desired capacity.

A slide valve 21 having a threaded shank 22 is fitted in the body s0 as to control the delivery of the materials through the bypass 16. When the valve 21 is in the position indicated communication is cut oft' through the by-pass, but the shank 22 being extended up through the top wall of the body and provided with a nut 23 may be adjusted upward so as to open a direct communication from the blow-ofi' pipe through the by-pass when it is ldesired to empty the boiler..V Ordinarily, however, or especially in connection with the automatic means referred to below the valve 21 is retained in its closed position indicated.

24 andv 25 are two pistons secured for simultaneous reciprocation and in spaced relation to each other by means of a rigid connector 26, said pistons being fitted for reciprocation in and 12. Thepiston 24: in the position of Fig. 1 lies at one side of the neck 19, remote the respective cylinders 11 between the passageway l5 p and the dome is cut off and the delivery from the dome through the neck 19 is Opened at the left of the piston 2li through the inner end of the cylinder 12 to the delivery pipe 17. This action or position of the piston nication with the delivery pipe, serves to bring the interior of the to atmospheric pressure. When I referred just above to the filling of the dome, as in Fig. 1, I, of course, contemplate that any air that may be trapped in the dome will simply be .subjected to the boiler pressure during the' filling action so that when the piston 24: ,is in its cut olf position as in Fig. 2 the pressure of such trapped air, remaining practically equivalent to the boiler pressure, will act to forcibly eject the contents of the domeinto the sewer.

Any suitable means may be provided to reciprocate the piston 24 for the purpose of alternately opening communication to and providing for delivery from the dome 20. To this end I employ the piston 25, which being fitted in the larger cylinder has the larger cross sectional area. At any conven'ient place as at the cap 27, I provide a live steam inlet for the cylinder 12. This inlet is indicated at28 and is provided with a manually controlled valve 29 through which the live 'steam or analogous high pressure fluid maybe delivered into the outer end of the cylinder 12 to act against the outer face 0f the piston 25 at any desired speed preferably relatively low speed. Since the area of the piston 25 is superior to that of the other piston, the pressure .fluid acting inward against the piston 2.5 from the posiwill move the double piston structure toward the right, and -as soonas the .piston 24 passes bevond the neclrr19 the contents of the dome being under high pressure will be discharged lthrough the delivery pipe 17 as shown by the arrows on Fig. 2, and the pistons will continue moving in the same direction until the piston 25n abuts against the annular shoulder 30 constituting the inner endof the wall of the cylinder 11. 31 indicates-a `pilot valve projecting through a `hole 32 in the piston 25 adjacent to one sidel of the piston and parallel to its aXis. This pilot valvev is slightly longer than the length of outer end a head 33. The inner end of the pilot valve while' the piston is `moving t0- ward thevright impinges against the shoulder 30 while the piston isapproaching the end of the stroke, and so the pilot valve is moved relatively toward the left bringing the channel 31 thereof into action to-establish communication directly from the cylinder 12 to the delivery pipe. The capacity of the port 31 is ordinarily greater than that of the inlet controlled by thevalve 29 and hence the power fluid admitted into the 24;, opening the dome to commit.

.dome ordinarily the piston and has on its y -cylinder' 12 while the pilot valve is open the pilot valve is thus closed the power pressure admitted against the. outer endb of the piston 25 will again drive the right with a repetition of theV action already described,ithus the valve 24 willbe reciprocated to and fro continually *by virtue of the steam pressure applied to the'piston 25, the rapidity of such reciprocation being determined by the design of the device Aand relative areas of the inlet and pilot ports.

The device is of a simple construction and is safe and reliable in operation requiring but a slight degree of expense for installation and in no manner interferes with the ordinary operation of the blowoff' pipe. If a complete blow-ofil is desired the valve 21 'will be opened as already stated.

I claimt p 1. In a blow-oifvalve, the combination of a body having a cylindrical chamber and having a passageway at one end leading from the attached pipe', a closed receptacle communicatingwith one side of the cylinder, a piston slidably fitted in the cylinder and movable to and fro acrossthe neclr leading to the receptacle, and means actuated automatically from the power fiuidto which the device is connected for reciprocating said piston.

2. Ina device of the character set forth, ,thecombination of a body, a pipe connecting the body .to a bilenr'saidbody including the piston toward Y a. cylinder, a closed receptacle having an open passageway leading from one side ,of the cylinder, a piston movable to and fro in `the cylinder across the passageway, the other end of the cylinder being open for free discharge of material from thereceptacle when the piston is at the remote side of the passageway from the outlet,and .automatic means acting upon the pistonto cause itto reciprocate intoa position to allow the contents. of the receptacle to discharge freely through the outlet. p A 8. In -an automatic valve, a hollow body including two cylinders one larger than the other in cross section, inlet means' at the .opposite ends of the body whereby a power fluid from the same source may be admitted into both cylinders, a pair lof rigidly connected pistons fitted in the respective cylinders, means to control the inflow of power iuid, the larger piston serving to overhalance and drive the smaller piston te tlie'op- 130 4to reciprocate the pistons posite end of the body, and means to automatically reduce the excessive pressure against the larger piston and so permit the constant pressure against the smaller piston in the opposite direction.

4. In an automatic Valve, the combination of a body having tWo co-aXial cylinders one larger than the other, a pair of pistons fitted in said cylinders, means rigidly connecting the pistons in spaced relation to each other,

means to admit power uid into the opposite ends of both cylinders to act against the outer ends of the pistons respectively, a discharge pipe from one side of the 'body adjacent to the inner meeting ends of the cylinders, and a pilot valve extending through the larger piston acting to open and close communication through said piston automatically at the respective ends of the reciprocations of the piston.

FRANK ROBERSON DEXTER.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patente, Washington, D. 0. 

